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Idrovo-Hidalgo T, Pignataro MF, Bredeston LM, Elias F, Herrera MG, Pavan MF, Foscaldi S, Suireszcz M, Fernández NB, Wetzler DE, Paván CH, Craig PO, Roman EA, Ruberto LAM, Noseda DG, Ibañez LI, Czibener C, Ugalde JE, Nadra AD, Santos J, D'Alessio C. Deglycosylated RBD produced in Pichia pastoris as a low-cost sera COVID-19 diagnosis tool and a vaccine candidate. Glycobiology 2024; 34:cwad089. [PMID: 37944064 DOI: 10.1093/glycob/cwad089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 10/26/2023] [Accepted: 11/01/2023] [Indexed: 11/12/2023] Open
Abstract
During the COVID-19 outbreak, numerous tools including protein-based vaccines have been developed. The methylotrophic yeast Pichia pastoris (synonymous to Komagataella phaffii) is an eukaryotic cost-effective and scalable system for recombinant protein production, with the advantages of an efficient secretion system and the protein folding assistance of the secretory pathway of eukaryotic cells. In a previous work, we compared the expression of SARS-CoV-2 Spike Receptor Binding Domain in P. pastoris with that in human cells. Although the size and glycosylation pattern was different between them, their protein structural and conformational features were indistinguishable. Nevertheless, since high mannose glycan extensions in proteins expressed by yeast may be the cause of a nonspecific immune recognition, we deglycosylated RBD in native conditions. This resulted in a highly pure, homogenous, properly folded and monomeric stable protein. This was confirmed by circular dichroism and tryptophan fluorescence spectra and by SEC-HPLC, which were similar to those of RBD proteins produced in yeast or human cells. Deglycosylated RBD was obtained at high yields in a single step, and it was efficient in distinguishing between SARS-CoV-2-negative and positive sera from patients. Moreover, when the deglycosylated variant was used as an immunogen, it elicited a humoral immune response ten times greater than the glycosylated form, producing antibodies with enhanced neutralizing power and eliciting a more robust cellular response. The proposed approach may be used to produce at a low cost, many antigens that require glycosylation to fold and express, but do not require glycans for recognition purposes.
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Affiliation(s)
- Tommy Idrovo-Hidalgo
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
| | - María F Pignataro
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
- Facultad de Farmacia y Bioquímica, Departamento de Química Biológica, Universidad de Buenos Aires, Junín 965 C1113AAD. Buenos Aires, Argentina
| | - Luis M Bredeston
- Facultad de Farmacia y Bioquímica, Departamento de Química Biológica, Universidad de Buenos Aires, Junín 965 C1113AAD. Buenos Aires, Argentina
- Instituto de Química y Fisicoquímica Biológicas, (IQUIFIB), CONICET-Universidad de Buenos Aires, Junín 956 C1113AAD, Buenos Aires, Argentina
| | - Fernanda Elias
- Consejo Nacional de Investigaciones Científicas y Técnicas-Fundación Pablo Cassará, Instituto de Ciencia y Tecnología Dr. César Milstein, Saladillo 2468 C1440FFX, Buenos Aires, Argentina
| | - María G Herrera
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
| | - María F Pavan
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE), CONICET-Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290 C1425FQB, Buenos Aires, Argentina
| | - Sabrina Foscaldi
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
| | - Mayra Suireszcz
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
| | - Natalia B Fernández
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
| | - Diana E Wetzler
- Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), CONICET-Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
| | - Carlos H Paván
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290 C1425FQB, Buenos Aires, Argentina
- Facultad de Farmacia y Bioquímica, LANAIS-PROEM, Instituto de Química y Fisicoquímica Biológicas, (IQUIFIB), CONICET-Universidad de Buenos Aires, Junín 956, C1113AAD, Buenos Aires, Argentina
| | - Patricio O Craig
- Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), CONICET-Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
| | - Ernesto A Roman
- Instituto de Química y Fisicoquímica Biológicas, (IQUIFIB), CONICET-Universidad de Buenos Aires, Junín 956 C1113AAD, Buenos Aires, Argentina
- Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
| | - Lucas A M Ruberto
- Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 965, C1113AAD, Buenos Aires, Argentina
- Instituto de Nanobiotecnología (NANOBIOTEC), CONICET-Universidad de Buenos Aires, Junín 965, C1113AAD, Buenos Aires, Argentina
- Instituto Antártico Argentino, Ministerio de Relaciones Exteriores y Culto, Av. 25 de Mayo 1147, B1650HMP, San Martín, Prov. de Buenos Aires, Argentina
| | - Diego G Noseda
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290 C1425FQB, Buenos Aires, Argentina
- Instituto de Investigaciones Biotecnológicas (IIBio), Universidad Nacional de San Martín-CONICET, Av. 25 de Mayo y Francia S/N, B1650HMP, San Martín, Prov. de Buenos Aires, Argentina
| | - Lorena I Ibañez
- Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE), CONICET-Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290 C1425FQB, Buenos Aires, Argentina
| | - Cecilia Czibener
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290 C1425FQB, Buenos Aires, Argentina
- Instituto de Investigaciones Biotecnológicas (IIBio), Universidad Nacional de San Martín-CONICET, Av. 25 de Mayo y Francia S/N, B1650HMP, San Martín, Prov. de Buenos Aires, Argentina
| | - Juan E Ugalde
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290 C1425FQB, Buenos Aires, Argentina
- Instituto de Investigaciones Biotecnológicas (IIBio), Universidad Nacional de San Martín-CONICET, Av. 25 de Mayo y Francia S/N, B1650HMP, San Martín, Prov. de Buenos Aires, Argentina
| | - Alejandro D Nadra
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290 C1425FQB, Buenos Aires, Argentina
| | - Javier Santos
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290 C1425FQB, Buenos Aires, Argentina
- Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
| | - Cecilia D'Alessio
- Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Godoy Cruz 2290 C1425FQB, Buenos Aires, Argentina
- Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Universidad de Buenos Aires, Intendente Güiraldes 2160, C1428EGA, Buenos Aires, Argentina
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2
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Santoni M, Gutierrez-Valdes N, Pivotto D, Zanichelli E, Rosa A, Sobrino-Mengual G, Balieu J, Lerouge P, Bardor M, Cecchetto R, Compri M, Mazzariol A, Ritala A, Avesani L. Performance of plant-produced RBDs as SARS-CoV-2 diagnostic reagents: a tale of two plant platforms. FRONTIERS IN PLANT SCIENCE 2024; 14:1325162. [PMID: 38239207 PMCID: PMC10794598 DOI: 10.3389/fpls.2023.1325162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 12/04/2023] [Indexed: 01/22/2024]
Abstract
The COVID-19 pandemic has underscored the need for rapid and cost-effective diagnostic tools. Serological tests, particularly those measuring antibodies targeting the receptor-binding domain (RBD) of the virus, play a pivotal role in tracking infection dynamics and vaccine effectiveness. In this study, we aimed to develop a simple enzyme-linked immunosorbent assay (ELISA) for measuring RBD-specific antibodies, comparing two plant-based platforms for diagnostic reagent production. We chose to retain RBD in the endoplasmic reticulum (ER) to prevent potential immunoreactivity issues associated with plant-specific glycans. We produced ER-retained RBD in two plant systems: a stable transformation of BY-2 plant cell culture (BY2-RBD) and a transient transformation in Nicotiana benthamiana using the MagnICON system (NB-RBD). Both systems demonstrated their suitability, with varying yields and production timelines. The plant-made proteins revealed unexpected differences in N-glycan profiles, with BY2-RBD displaying oligo-mannosidic N-glycans and NB-RBD exhibiting a more complex glycan profile. This difference may be attributed to higher recombinant protein synthesis in the N. benthamiana system, potentially overloading the ER retention signal, causing some proteins to traffic to the Golgi apparatus. When used as diagnostic reagents in ELISA, BY2-RBD outperformed NB-RBD in terms of sensitivity, specificity, and correlation with a commercial kit. This discrepancy may be due to the distinct glycan profiles, as complex glycans on NB-RBD may impact immunoreactivity. In conclusion, our study highlights the potential of plant-based systems for rapid diagnostic reagent production during emergencies. However, transient expression systems, while offering shorter timelines, introduce higher heterogeneity in recombinant protein forms, necessitating careful consideration in serological test development.
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Affiliation(s)
| | | | - Denise Pivotto
- Department of Biotechnology, University of Verona, Verona, Italy
| | - Elena Zanichelli
- Department of Biotechnology, University of Verona, Verona, Italy
| | | | - Guillermo Sobrino-Mengual
- Université de Rouen Normandie, Normandie Univ, GlycoMEV UR 4358, SFR Normandie Végétal FED 4277, Innovation Chimie Carnot, IRIB, GDR CNRS Chemobiologie, RMT BESTIM, Rouen, France
- Applied Plant Biotechnology Group, Department of Plant Production and Forestry Science, University of Lleida-Agrotecnio CERCA Center, Lleida, Spain
| | - Juliette Balieu
- Université de Rouen Normandie, Normandie Univ, GlycoMEV UR 4358, SFR Normandie Végétal FED 4277, Innovation Chimie Carnot, IRIB, GDR CNRS Chemobiologie, RMT BESTIM, Rouen, France
| | - Patrice Lerouge
- Université de Rouen Normandie, Normandie Univ, GlycoMEV UR 4358, SFR Normandie Végétal FED 4277, Innovation Chimie Carnot, IRIB, GDR CNRS Chemobiologie, RMT BESTIM, Rouen, France
| | - Muriel Bardor
- Université de Rouen Normandie, Normandie Univ, GlycoMEV UR 4358, SFR Normandie Végétal FED 4277, Innovation Chimie Carnot, IRIB, GDR CNRS Chemobiologie, RMT BESTIM, Rouen, France
| | - Riccardo Cecchetto
- Department of Diagnostics and Public Health, Microbiology Section, University of Verona, Verona, Italy
| | - Monica Compri
- Azienda Ospedaliera Universitaria, UOC Microbiologia e Virologia, Verona, Italy
| | - Annarita Mazzariol
- Department of Diagnostics and Public Health, Microbiology Section, University of Verona, Verona, Italy
| | - Anneli Ritala
- VTT Technical Research Centre of Finland Ltd., Espoo, Finland
| | - Linda Avesani
- Department of Biotechnology, University of Verona, Verona, Italy
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3
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Mamedov T, Yuksel D, Gurbuzaslan I, Gulec B, Mammadova G, Ozdarendeli A, Pavel STI, Yetiskin H, Kaplan B, Uygut MA, Hasanova G. SARS-CoV-2 spike protein S1 subunit induces potent neutralizing responses in mice and is effective against Delta and Omicron variants. FRONTIERS IN PLANT SCIENCE 2023; 14:1290042. [PMID: 38034565 PMCID: PMC10682712 DOI: 10.3389/fpls.2023.1290042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 10/25/2023] [Indexed: 12/02/2023]
Abstract
SARS-CoV-2, the virus responsible for the COVID-19 pandemic, belongs to the betacoronavirus genus. This virus has a high mutation rate, which rapidly evolves into new variants with different properties, such as increased transmissibility or immune evasion. Currently, the most prevalent global SARS-CoV-2 variant is Omicron, which is more transmissible than previous variants. Current available vaccines may be less effective against some currently existing SARS-CoV-2 variants, including the Omicron variant. The S1 subunit of the spike protein of SARS-CoV-2 has been a major target for COVID-19 vaccine development. It plays a crucial role in the virus's entry into host cells and is the primary target for neutralizing antibodies. In this study, the S1 subunit of the spike protein of SARS-CoV-2 was engineered and produced at a high level in Nicotiana benthamiana plant. The expression level of the recombinant S1 protein was greater than the 0.5-g/kg fresh weight, and the purification yield was at least ~0.3 g of pure protein/kg of plant biomass, which would make a plant-produced S1 antigen an ideal vaccine candidate for commercialization. Purified, the plant-produced SARS-CoV-2 S1 protein exhibited significantly higher binding to the SARS-CoV-2 receptor, angiotensin-converting enzyme 2 (ACE2). Moreover, we also show that recombinant S1 protein/antigen-elicited antibodies can neutralize the Delta or Omicron variants. Collectively, our results demonstrate that a plant-produced S1 antigen could be a promising vaccine candidate against SARS-CoV-2 variants including Omicron.
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Affiliation(s)
- Tarlan Mamedov
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Türkiye
- Institute of Molecular Biology and Biotechnologies, Ministry of Science and Education of Azerbaijan, Baku, Azerbaijan
| | - Damla Yuksel
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Türkiye
| | - Irem Gurbuzaslan
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Türkiye
| | - Burcu Gulec
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Türkiye
| | - Gulshan Mammadova
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Türkiye
| | - Aykut Ozdarendeli
- Department of Microbiology, Medical Faculty, Erciyes University, Kayseri, Türkiye
- Vaccine Research, Development and Application Center, Erciyes University, Kayseri, Türkiye
| | - Shaikh Terkis Islam Pavel
- Department of Microbiology, Medical Faculty, Erciyes University, Kayseri, Türkiye
- Vaccine Research, Development and Application Center, Erciyes University, Kayseri, Türkiye
| | - Hazel Yetiskin
- Department of Microbiology, Medical Faculty, Erciyes University, Kayseri, Türkiye
- Vaccine Research, Development and Application Center, Erciyes University, Kayseri, Türkiye
| | - Busra Kaplan
- Department of Microbiology, Medical Faculty, Erciyes University, Kayseri, Türkiye
- Vaccine Research, Development and Application Center, Erciyes University, Kayseri, Türkiye
| | - Muhammet Ali Uygut
- Department of Microbiology, Medical Faculty, Erciyes University, Kayseri, Türkiye
| | - Gulnara Hasanova
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Türkiye
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4
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Strasser R. Plant glycoengineering for designing next-generation vaccines and therapeutic proteins. Biotechnol Adv 2023; 67:108197. [PMID: 37315875 DOI: 10.1016/j.biotechadv.2023.108197] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 06/05/2023] [Accepted: 06/06/2023] [Indexed: 06/16/2023]
Abstract
Protein glycosylation has a huge impact on biological processes in all domains of life. The type of glycan present on a recombinant glycoprotein depends on protein intrinsic features and the glycosylation repertoire of the cell type used for expression. Glycoengineering approaches are used to eliminate unwanted glycan modifications and to facilitate the coordinated expression of glycosylation enzymes or whole metabolic pathways to furnish glycans with distinct modifications. The formation of tailored glycans enables structure-function studies and optimization of therapeutic proteins used in different applications. While recombinant proteins or proteins from natural sources can be in vitro glycoengineered using glycosyltransferases or chemoenzymatic synthesis, many approaches use genetic engineering involving the elimination of endogenous genes and introduction of heterologous genes to cell-based production systems. Plant glycoengineering enables the in planta production of recombinant glycoproteins with human or animal-type glycans that resemble natural glycosylation or contain novel glycan structures. This review summarizes key achievements in glycoengineering of plants and highlights current developments aiming to make plants more suitable for the production of a diverse range of recombinant glycoproteins for innovative therapies.
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Affiliation(s)
- Richard Strasser
- Institute of Plant Biotechnology and Cell Biology, Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria.
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5
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Herman X, Far J, Peeters M, Quinton L, Chaumont F, Navarre C. In vivo deglycosylation of recombinant glycoproteins in tobacco BY-2 cells. PLANT BIOTECHNOLOGY JOURNAL 2023; 21:1773-1784. [PMID: 37266972 PMCID: PMC10440984 DOI: 10.1111/pbi.14074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 03/21/2023] [Accepted: 04/29/2023] [Indexed: 06/03/2023]
Abstract
Production of recombinant pharmaceutical glycoproteins has been carried out in multiple expression systems. However, N-glycosylation, which increases heterogeneity and raises safety concerns due to the presence of non-human residues, is usually not controlled. The presence and composition of N-glycans are also susceptible to affect protein stability, function and immunogenicity. To tackle these issues, we are developing glycoengineered Nicotiana tabacum Bright Yellow-2 (BY-2) cell lines through knock out and ectopic expression of genes involved in the N-glycosylation pathway. Here, we report on the generation of BY-2 cell lines producing deglycosylated proteins. To this end, endoglycosidase T was co-expressed with an immunoglobulin G or glycoprotein B of human cytomegalovirus in BY-2 cell lines producing only high mannose N-glycans. Endoglycosidase T cleaves high mannose N-glycans to generate single, asparagine-linked, N-acetylglucosamine residues. The N-glycosylation profile of the secreted antibody was determined by mass spectrometry analysis. More than 90% of the N-glycans at the conserved Asn297 site were deglycosylated. Likewise, extensive deglycosylation of glycoprotein B, which possesses 18 N-glycosylation sites, was observed. N-glycan composition of gB glycovariants was assessed by in vitro enzymatic mobility shift assay and proven to be consistent with the expected glycoforms. Comparison of IgG glycovariants by differential scanning fluorimetry revealed a significant impact of the N-glycosylation pattern on the thermal stability. Production of deglycosylated pharmaceutical proteins in BY-2 cells expands the set of glycoengineered BY-2 cell lines.
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Affiliation(s)
- Xavier Herman
- Louvain Institute of Biomolecular Science and TechnologyUCLouvainLouvain‐la‐NeuveBelgium
| | - Johann Far
- Mass Spectrometry Laboratory‐MolSys Research UnitULiegeLiègeBelgium
| | - Marie Peeters
- Louvain Institute of Biomolecular Science and TechnologyUCLouvainLouvain‐la‐NeuveBelgium
| | - Loïc Quinton
- Mass Spectrometry Laboratory‐MolSys Research UnitULiegeLiègeBelgium
| | - François Chaumont
- Louvain Institute of Biomolecular Science and TechnologyUCLouvainLouvain‐la‐NeuveBelgium
| | - Catherine Navarre
- Louvain Institute of Biomolecular Science and TechnologyUCLouvainLouvain‐la‐NeuveBelgium
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6
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Mamedov T, Yuksel D, Gurbuzaslan I, Ilgin M, Gulec B, Mammadova G, Ozdarendeli A, Pavel STI, Yetiskin H, Kaplan B, Uygut MA, Hasanova G. Plant-produced RBD and cocktail-based vaccine candidates are highly effective against SARS-CoV-2, independently of its emerging variants. FRONTIERS IN PLANT SCIENCE 2023; 14:1202570. [PMID: 37600182 PMCID: PMC10433747 DOI: 10.3389/fpls.2023.1202570] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Accepted: 07/12/2023] [Indexed: 08/22/2023]
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel and highly pathogenic coronavirus that caused an outbreak in Wuhan City, China, in 2019 and then spread rapidly throughout the world. Although several coronavirus disease 2019 (COVID-19) vaccines are currently available for mass immunization, they are less effective against emerging SARS-CoV-2 variants, especially the Omicron (B.1.1.529). Recently, we successfully produced receptor-binding domain (RBD) variants of the spike (S) protein of SARS-CoV-2 and an antigen cocktail in Nicotiana benthamiana, which are highly produced in plants and elicited high-titer antibodies with potent neutralizing activity against SARS-CoV-2. In this study, based on neutralization ability, we demonstrate that plant-produced RBD and cocktail-based vaccine candidates are highly effective against SARS-CoV-2, independently of its emerging variants. These data demonstrate that plant-produced RBD and cocktail-based proteins are the most promising vaccine candidates and may protect against Delta and Omicron-mediated COVID-19. This is the first report describing vaccines against SARS-CoV-2, which demonstrate significant activities against Delta and Omicron variants.
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Affiliation(s)
- Tarlan Mamedov
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Türkiye
- Institute of Molecular Biology and Biotechnologies, Ministry of Science and Education, Republic of Azerbaijan, Baku, Azerbaijan
| | - Damla Yuksel
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Türkiye
| | - Irem Gurbuzaslan
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Türkiye
| | - Merve Ilgin
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Türkiye
| | - Burcu Gulec
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Türkiye
| | - Gulshan Mammadova
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Türkiye
| | - Aykut Ozdarendeli
- Department of Microbiology, Medical Faculty, Erciyes University, Kayseri, Türkiye
- Vaccine Research, Development and Application Center, Erciyes University, Kayseri, Türkiye
| | - Shaikh Terkis Islam Pavel
- Department of Microbiology, Medical Faculty, Erciyes University, Kayseri, Türkiye
- Vaccine Research, Development and Application Center, Erciyes University, Kayseri, Türkiye
| | - Hazel Yetiskin
- Department of Microbiology, Medical Faculty, Erciyes University, Kayseri, Türkiye
- Vaccine Research, Development and Application Center, Erciyes University, Kayseri, Türkiye
| | - Busra Kaplan
- Department of Microbiology, Medical Faculty, Erciyes University, Kayseri, Türkiye
- Vaccine Research, Development and Application Center, Erciyes University, Kayseri, Türkiye
| | - Muhammet Ali Uygut
- Department of Microbiology, Medical Faculty, Erciyes University, Kayseri, Türkiye
| | - Gulnara Hasanova
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Türkiye
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7
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Singh R, Lin S, Nair SK, Shi Y, Daniell H. Oral booster vaccine antigen-Expression of full-length native SARS-CoV-2 spike protein in lettuce chloroplasts. PLANT BIOTECHNOLOGY JOURNAL 2023; 21:887-889. [PMID: 36577691 PMCID: PMC9880656 DOI: 10.1111/pbi.13993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 12/20/2022] [Accepted: 12/22/2022] [Indexed: 05/04/2023]
Affiliation(s)
- Rahul Singh
- Department of Basic and Translational Sciences, School of Dental MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Shina Lin
- Department of Basic and Translational Sciences, School of Dental MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Smruti K. Nair
- Department of Basic and Translational Sciences, School of Dental MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Yao Shi
- Department of Basic and Translational Sciences, School of Dental MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Henry Daniell
- Department of Basic and Translational Sciences, School of Dental MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
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8
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Margolin E, Schäfer G, Allen JD, Gers S, Woodward J, Sutherland AD, Blumenthal M, Meyers A, Shaw ML, Preiser W, Strasser R, Crispin M, Williamson AL, Rybicki EP, Chapman R. A plant-produced SARS-CoV-2 spike protein elicits heterologous immunity in hamsters. FRONTIERS IN PLANT SCIENCE 2023; 14:1146234. [PMID: 36959936 PMCID: PMC10028082 DOI: 10.3389/fpls.2023.1146234] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 02/17/2023] [Indexed: 06/16/2023]
Abstract
Molecular farming of vaccines has been heralded as a cheap, safe and scalable production platform. In reality, however, differences in the plant biosynthetic machinery, compared to mammalian cells, can complicate the production of viral glycoproteins. Remodelling the secretory pathway presents an opportunity to support key post-translational modifications, and to tailor aspects of glycosylation and glycosylation-directed folding. In this study, we applied an integrated host and glyco-engineering approach, NXS/T Generation™, to produce a SARS-CoV-2 prefusion spike trimer in Nicotiana benthamiana as a model antigen from an emerging virus. The size exclusion-purified protein exhibited a characteristic prefusion structure when viewed by transmission electron microscopy, and this was indistinguishable from the equivalent mammalian cell-produced antigen. The plant-produced protein was decorated with under-processed oligomannose N-glycans and exhibited a site occupancy that was comparable to the equivalent protein produced in mammalian cell culture. Complex-type glycans were almost entirely absent from the plant-derived material, which contrasted against the predominantly mature, complex glycans that were observed on the mammalian cell culture-derived protein. The plant-derived antigen elicited neutralizing antibodies against both the matched Wuhan and heterologous Delta SARS-CoV-2 variants in immunized hamsters, although titres were lower than those induced by the comparator mammalian antigen. Animals vaccinated with the plant-derived antigen exhibited reduced viral loads following challenge, as well as significant protection from SARS-CoV-2 disease as evidenced by reduced lung pathology, lower viral loads and protection from weight loss. Nonetheless, animals immunized with the mammalian cell-culture-derived protein were better protected in this challenge model suggesting that more faithfully reproducing the native glycoprotein structure and associated glycosylation of the antigen may be desirable.
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Affiliation(s)
- Emmanuel Margolin
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Wellcome Trust Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| | - Georgia Schäfer
- Wellcome Trust Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- International Centre for Genetic Engineering and Biotechnology, Observatory, Cape Town, Cape Town, South Africa
| | - Joel D Allen
- School of Biological Sciences and Institute of Life Sciences, University of Southampton, Southampton, United Kingdom
| | | | - Jeremy Woodward
- Electron Microscope Unit, University of Cape Town, Cape Town, South Africa
| | - Andrew D Sutherland
- Division of Medical Virology, Faculty of Medicine and Health Sciences, Stellenbosch University Tygerberg Campus, Cape Town, South Africa
| | - Melissa Blumenthal
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- International Centre for Genetic Engineering and Biotechnology, Observatory, Cape Town, Cape Town, South Africa
| | - Ann Meyers
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| | - Megan L Shaw
- Department of Medical Biosciences, University of the Western Cape, Cape Town, South Africa
| | - Wolfgang Preiser
- Division of Medical Virology, Faculty of Medicine and Health Sciences, Stellenbosch University Tygerberg Campus, Cape Town, South Africa
| | - Richard Strasser
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Max Crispin
- School of Biological Sciences and Institute of Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Anna-Lise Williamson
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Edward P Rybicki
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| | - Ros Chapman
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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9
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England C, TrejoMartinez J, PerezSanchez P, Karki U, Xu J. Plants as Biofactories for Therapeutic Proteins and Antiviral Compounds to Combat COVID-19. Life (Basel) 2023; 13:617. [PMID: 36983772 PMCID: PMC10054913 DOI: 10.3390/life13030617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 02/14/2023] [Accepted: 02/20/2023] [Indexed: 02/25/2023] Open
Abstract
The outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) had a profound impact on the world's health and economy. Although the end of the pandemic may come in 2023, it is generally believed that the virus will not be completely eradicated. Most likely, the disease will become an endemicity. The rapid development of vaccines of different types (mRNA, subunit protein, inactivated virus, etc.) and some other antiviral drugs (Remdesivir, Olumiant, Paxlovid, etc.) has provided effectiveness in reducing COVID-19's impact worldwide. However, the circulating SARS-CoV-2 virus has been constantly mutating with the emergence of multiple variants, which makes control of COVID-19 difficult. There is still a pressing need for developing more effective antiviral drugs to fight against the disease. Plants have provided a promising production platform for both bioactive chemical compounds (small molecules) and recombinant therapeutics (big molecules). Plants naturally produce a diverse range of bioactive compounds as secondary metabolites, such as alkaloids, terpenoids/terpenes and polyphenols, which are a rich source of countless antiviral compounds. Plants can also be genetically engineered to produce valuable recombinant therapeutics. This molecular farming in plants has an unprecedented opportunity for developing vaccines, antibodies, and other biologics for pandemic diseases because of its potential advantages, such as low cost, safety, and high production volume. This review summarizes the latest advancements in plant-derived drugs used to combat COVID-19 and discusses the prospects and challenges of the plant-based production platform for antiviral agents.
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Affiliation(s)
- Corbin England
- Arkansas Biosciences Institute, Arkansas State University, Jonesboro, AR 72401, USA
- Molecular Biosciences Program, Arkansas State University, Jonesboro, AR 72401, USA
| | | | - Paula PerezSanchez
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401, USA
| | - Uddhab Karki
- Arkansas Biosciences Institute, Arkansas State University, Jonesboro, AR 72401, USA
- Molecular Biosciences Program, Arkansas State University, Jonesboro, AR 72401, USA
| | - Jianfeng Xu
- Arkansas Biosciences Institute, Arkansas State University, Jonesboro, AR 72401, USA
- College of Agriculture, Arkansas State University, Jonesboro, AR 72401, USA
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10
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High-Yield Production of Chimeric Hepatitis E Virus-Like Particles Bearing the M2e Influenza Epitope and Receptor Binding Domain of SARS-CoV-2 in Plants Using Viral Vectors. Int J Mol Sci 2022; 23:ijms232415684. [PMID: 36555326 PMCID: PMC9779006 DOI: 10.3390/ijms232415684] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/02/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022] Open
Abstract
Capsid protein of Hepatitis E virus (HEV) is capable of self-assembly into virus-like particles (VLPs) when expressed in Nicotiana benthamiana plants. Such VLPs could be used as carriers of antigens for vaccine development. In this study, we obtained VLPs based on truncated coat protein of HEV bearing the M2e peptide of Influenza A virus or receptor-binding domain of SARS-CoV-2 spike glycoprotein (RBD). We optimized the immunogenic epitopes' presentation by inserting them into the protruding domain of HEV ORF2 at position Tyr485. The fusion proteins were expressed in Nicotiana benthamiana plants using self-replicating potato virus X (PVX)-based vector. The fusion protein HEV/M2, targeted to the cytosol, was expressed at the level of about 300-400 μg per gram of fresh leaf tissue and appeared to be soluble. The fusion protein was purified using metal affinity chromatography under native conditions with the final yield about 200 μg per gram of fresh leaf tissue. The fusion protein HEV/RBD, targeted to the endoplasmic reticulum, was expressed at about 80-100 μg per gram of fresh leaf tissue; the yield after purification was up to 20 μg per gram of fresh leaf tissue. The recombinant proteins HEV/M2 and HEV/RBD formed nanosized virus-like particles that could be recognized by antibodies against inserted epitopes. The ELISA assay showed that antibodies of COVID-19 patients can bind plant-produced HEV/RBD virus-like particles. This study shows that HEV capsid protein is a promising carrier for presentation of foreign antigen.
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11
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Mardanova ES, Kotlyarov RY, Ravin NV. Rapid Transient Expression of Receptor-Binding Domain of SARS-CoV-2 and the Conserved M2e Peptide of Influenza A Virus Linked to Flagellin in Nicotiana benthamiana Plants Using Self-Replicating Viral Vector. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11243425. [PMID: 36559537 PMCID: PMC9785242 DOI: 10.3390/plants11243425] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 11/30/2022] [Accepted: 12/04/2022] [Indexed: 06/12/2023]
Abstract
The development of recombinant vaccines against SARS-CoV-2 and influenza A is an important task. The combination of the conserved influenza A antigen, the extracellular domain of the transmembrane protein M2 (M2e), and the receptor-binding domain of the SARS-CoV-2 spike glycoprotein (RBD) provides the opportunity to develop a bivalent vaccine against these infections. The fusion of antigens with bacterial flagellin, the ligand for Toll-like receptor 5 and potent mucosal adjuvant, may increase the immunogenicity of the candidate vaccines and enable intranasal immunization. In this study, we report the transient expression of RBD alone, RBD coupled with four copies of M2e, and fusions of RBD and RBD-4M2e with flagellin in Nicotiana benthamiana plants using the self-replicating potato virus X-based vector pEff. The yields of purified recombinant proteins per gram of fresh leaf tissue were about 20 µg for RBD, 50-60 µg for RBD-4M2e and the fusion of RBD with flagellin, and about 90 µg for RBD-4M2e fused to flagellin. Targeting to the endoplasmic reticulum enabled the production of glycosylated recombinant proteins comprising RBD. Our results show that plant-produced RBD and RBD-4M2e could be further used for the development of subunit vaccines against COVID-19 and a bivalent vaccine against COVID-19 and influenza A, while flagellin fusions could be used for the development of intranasal vaccines.
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12
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Fleury H. HIV and SARS-CoV-2 Pathogenesis and Vaccine Development. Viruses 2022; 14:v14122598. [PMID: 36560600 PMCID: PMC9781173 DOI: 10.3390/v14122598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 11/17/2022] [Indexed: 11/24/2022] Open
Abstract
Although both HIV and SARS-CoV-2 are associated with pandemics, they are transmitted differently [...]
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Affiliation(s)
- Herve Fleury
- Université de Bordeaux et CNRS, 33076 Bordeaux, France
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13
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Rebelo BA, Folgado A, Ferreira AC, Abranches R. Production of the SARS-CoV-2 Spike protein and its Receptor Binding Domain in plant cell suspension cultures. FRONTIERS IN PLANT SCIENCE 2022; 13:995429. [PMID: 36340353 PMCID: PMC9634662 DOI: 10.3389/fpls.2022.995429] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 09/20/2022] [Indexed: 05/29/2023]
Abstract
The COVID-19 pandemic, caused by the worldwide spread of SARS-CoV-2, has prompted the scientific community to rapidly develop efficient and specific diagnostics and therapeutics. A number of avenues have been explored, including the manufacture of COVID-related proteins to be used as reagents for diagnostics or treatment. The production of RBD and Spike proteins was previously achieved in eukaryotic cells, mainly mammalian cell cultures, while the production in microbial systems has been unsuccessful until now. Here we report the effective production of SARS-CoV-2 proteins in two plant model systems. We established transgenic tobacco BY-2 and Medicago truncatula A17 cell suspension cultures stably producing the full-length Spike and RBD recombinant proteins. For both proteins, various glycoforms were obtained, with higher yields in Medicago cultures than BY-2. This work highlights that RBD and Spike can be secreted into the culture medium, which will impact subsequent purification and downstream processing costs. Analysis of the culture media indicated the presence of the high molecular weight Spike protein of SARS-CoV-2. Although the production yields still need improvement to compete with mammalian systems, this is the first report showing that plant cell suspension cultures are able to produce the high molecular weight Spike protein. This finding strengthens the potential of plant cell cultures as production platforms for large complex proteins.
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14
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Investigation of the N-Glycosylation of the SARS-CoV-2 S Protein Contained in VLPs Produced in Nicotiana benthamiana. Molecules 2022; 27:molecules27165119. [PMID: 36014368 PMCID: PMC9412417 DOI: 10.3390/molecules27165119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 07/29/2022] [Accepted: 08/04/2022] [Indexed: 11/17/2022] Open
Abstract
The emergence of the SARS-CoV-2 coronavirus pandemic in China in late 2019 led to the fast development of efficient therapeutics. Of the major structural proteins encoded by the SARS-CoV-2 genome, the SPIKE (S) protein has attracted considerable research interest because of the central role it plays in virus entry into host cells. Therefore, to date, most immunization strategies aim at inducing neutralizing antibodies against the surface viral S protein. The SARS-CoV-2 S protein is heavily glycosylated with 22 predicted N-glycosylation consensus sites as well as numerous mucin-type O-glycosylation sites. As a consequence, O- and N-glycosylations of this viral protein have received particular attention. Glycans N-linked to the S protein are mainly exposed at the surface and form a shield-masking specific epitope to escape the virus antigenic recognition. In this work, the N-glycosylation status of the S protein within virus-like particles (VLPs) produced in Nicotiana benthamiana (N. benthamiana) was investigated using a glycoproteomic approach. We show that 20 among the 22 predicted N-glycosylation sites are dominated by complex plant N-glycans and one carries oligomannoses. This suggests that the SARS-CoV-2 S protein produced in N. benthamiana adopts an overall 3D structure similar to that of recombinant homologues produced in mammalian cells.
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15
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Chauhan M, Bhardwaj VK, Kumar A, Kumar V, Kumar P, Enayathullah MG, Thomas J, George J, Kumar BK, Purohit R, Kumar A, Kumar S. Theaflavin 3-gallate inhibits the main protease (M pro) of SARS-CoV-2 and reduces its count in vitro. Sci Rep 2022; 12:13146. [PMID: 35908093 PMCID: PMC9338964 DOI: 10.1038/s41598-022-17558-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 07/27/2022] [Indexed: 12/26/2022] Open
Abstract
The main protease (Mpro) of SARS-CoV-2 has been recognized as an attractive drug target because of its central role in viral replication. Our previous preliminary molecular docking studies showed that theaflavin 3-gallate (a natural bioactive molecule derived from theaflavin and found in high abundance in black tea) exhibited better docking scores than repurposed drugs (Atazanavir, Darunavir, Lopinavir). In this study, conventional and steered MD-simulations analyses revealed stronger interactions of theaflavin 3-gallate with the active site residues of Mpro than theaflavin and a standard molecule GC373 (a known inhibitor of Mpro and novel broad-spectrum anti-viral agent). Theaflavin 3-gallate inhibited Mpro protein of SARS-CoV-2 with an IC50 value of 18.48 ± 1.29 μM. Treatment of SARS-CoV-2 (Indian/a3i clade/2020 isolate) with 200 μM of theaflavin 3-gallate in vitro using Vero cells and quantifying viral transcripts demonstrated reduction of viral count by 75% (viral particles reduced from Log106.7 to Log106.1). Overall, our findings suggest that theaflavin 3-gallate effectively targets the Mpro thus limiting the replication of the SARS-CoV-2 virus in vitro.
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Affiliation(s)
- Mahima Chauhan
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India.,Academy of Scientific and Innovative Research, Ghaziabad, Uttar Pradesh, 201002, India
| | - Vijay Kumar Bhardwaj
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India.,Academy of Scientific and Innovative Research, Ghaziabad, Uttar Pradesh, 201002, India.,Structural Bioinformatics Lab, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India
| | - Asheesh Kumar
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India.,Academy of Scientific and Innovative Research, Ghaziabad, Uttar Pradesh, 201002, India
| | - Vinod Kumar
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India
| | - Pawan Kumar
- Academy of Scientific and Innovative Research, Ghaziabad, Uttar Pradesh, 201002, India.,Chemical Technology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India
| | - M Ghalib Enayathullah
- CSIR-Center for Cellular and Molecular Biology, Annexe-II, Medical Biotechnology Complex, Uppal Road, Hyderabad, Telangana, 500007, India
| | - Jessie Thomas
- CSIR-Center for Cellular and Molecular Biology, Annexe-II, Medical Biotechnology Complex, Uppal Road, Hyderabad, Telangana, 500007, India
| | - Joel George
- CSIR-Center for Cellular and Molecular Biology, Annexe-II, Medical Biotechnology Complex, Uppal Road, Hyderabad, Telangana, 500007, India
| | - Bokara Kiran Kumar
- CSIR-Center for Cellular and Molecular Biology, Annexe-II, Medical Biotechnology Complex, Uppal Road, Hyderabad, Telangana, 500007, India.
| | - Rituraj Purohit
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India. .,Academy of Scientific and Innovative Research, Ghaziabad, Uttar Pradesh, 201002, India. .,Structural Bioinformatics Lab, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India.
| | - Arun Kumar
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India. .,Academy of Scientific and Innovative Research, Ghaziabad, Uttar Pradesh, 201002, India.
| | - Sanjay Kumar
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India
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16
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Mei X, Gu P, Shen C, Lin X, Li J. Computer-Based Immunoinformatic Analysis to Predict Candidate T-Cell Epitopes for SARS-CoV-2 Vaccine Design. Front Immunol 2022; 13:847617. [PMID: 35432316 PMCID: PMC9006954 DOI: 10.3389/fimmu.2022.847617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 02/28/2022] [Indexed: 11/15/2022] Open
Abstract
Since the first outbreak of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2019, its high infectivity led to its prevalence around the world in an exceptionally short time. Efforts have been made to control the ongoing outbreak, and among them, vaccine developments are going on high priority. New clinical trials add to growing evidence that vaccines from many countries were highly effective at preventing SARS-CoV-2 virus infection. One of them is B cell-based vaccines, which were common during a pandemic. However, neutralizing antibody therapy becomes less effective when viruses mutate. In order to tackle the problem, we focused on T-cell immune mechanism. In this study, the mutated strains of the virus were selected globally from India (B.1.617.1 and B.1.617.2), United Kingdom (B.1.1.7), South Africa (B.1.351), and Brazil (P.1), and the overlapping peptides were collected based on mutation sites of S-protein. After that, residue scanning was used to predict the affinity between overlapping peptide and HLA-A*11:01, the most frequent human leukocyte antigen (HLA) allele among the Chinese population. Then, the binding free energy was evaluated with molecular docking to further verify the affinity changes after the mutations happen in the virus genomes. The affinity test results of three epitopes on spike protein from experimental validation were consistent with our predicted results, thereby supporting the inclusion of the epitope 374FSTFKCYGL382 in future vaccine design and providing a useful reference route to improve vaccine development.
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Affiliation(s)
- Xueyin Mei
- Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, School of Life Science and Technology, Southeast University, Nanjing, China
| | - Pan Gu
- Department of Math and Computer Sciences, College of Letters and Science, University of Wisconsin-Madison, Madison, WI, United States
| | - Chuanlai Shen
- Department of Microbiology and Immunology, Medical School of Southeast University, Nanjing, China
| | - Xue Lin
- Department of Bioinformatics, School of Biomedical Engineering and Informatics, Nanjing Medical University, Nanjing, China
| | - Jian Li
- Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, School of Life Science and Technology, Southeast University, Nanjing, China
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17
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Ruocco V, Strasser R. Transient Expression of Glycosylated SARS-CoV-2 Antigens in Nicotiana benthamiana. PLANTS (BASEL, SWITZERLAND) 2022; 11:1093. [PMID: 35448821 PMCID: PMC9033091 DOI: 10.3390/plants11081093] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 04/12/2022] [Accepted: 04/15/2022] [Indexed: 12/14/2022]
Abstract
The current COVID-19 pandemic very dramatically shows that the world lacks preparedness for novel viral diseases. In addition to newly emerging viruses, many known pathogenic viruses such as influenza are constantly evolving, leading to frequent outbreaks with severe diseases and deaths. Hence, infectious viruses are a recurrent burden to our daily life, and powerful strategies to stop the spread of human pathogens and disease progression are of utmost importance. Transient plant-based protein expression is a technology that allows fast and highly flexible manufacturing of recombinant viral proteins and, thus, can contribute to infectious disease detection and prevention. This review highlights recent progress in the transient production of viral glycoproteins in N. benthamiana with a focus on SARS-CoV-2-derived viral antigens.
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Affiliation(s)
| | - Richard Strasser
- Department of Applied Genetics and Cell Biology, Institute of Plant Biotechnology and Cell Biology, University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria;
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18
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Velusamy P, Kiruba K, Su CH, Arun V, Anbu P, Gopinath SCB, Vaseeharan B. SARS-CoV-2 spike protein: Site-specific breakpoints for the development of COVID-19 vaccines. JOURNAL OF KING SAUD UNIVERSITY. SCIENCE 2021; 33:101648. [PMID: 34690467 PMCID: PMC8523302 DOI: 10.1016/j.jksus.2021.101648] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 09/08/2021] [Accepted: 10/07/2021] [Indexed: 05/08/2023]
Abstract
SARS-CoV2 is a member of human coronaviruses and is the causative agent of the present pandemic COVID-19 virus. In order to control COVID-19, studies on viral structure and mechanism of infectivity and pathogenicity are sorely needed. The spike (S) protein is comprised of S1 & S2 subunits. These spike protein subunits enable viral attachment by binding to the host cell via ACE-2 (angiotensin converting enzyme-2) receptor, thus facilitating the infection. During viral entry, one of the key steps is the cleavage of the S1-S2 spike protein subunits via surface TMPRSS2 (transmembrane protease serine 2) and results in viral infection. Hence, the S-protein is critical for the viral attachment and penetration into the host. The rapid advancement of our knowledge on the structural and functional aspects of the spike protein could lead to development of numerous candidate vaccines against SARS-CoV2. Here the authors discuss about the structure of spike protein and explore its related functions. Our aim is to provide a better understanding that may aid in fighting against CoVID-19 and its treatment.
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Affiliation(s)
- Palaniyandi Velusamy
- Research and Development Wing, Central Research Laboratory, Sree Balaji Medical College and Hospital, Bharath Institute of Higher Education and Research (BIHER), Chennai- 600 044, TN, India
| | - Kannan Kiruba
- Department of Biotechnology, University of Madras, Guindy Campus, Chennai 600 025, TN, India
| | - Chia-Hung Su
- Department of Chemical Engineering, Ming Chi University of Technology, Taishan, Taipei 24301, Taiwan
| | - Viswanathan Arun
- Department of Biotechnology SRFBMST, Sri Ramachandra Institute of Higher Education and Research, Porur, Chennai 600 116, TN, India
| | - Periasamy Anbu
- Department of Biological Engineering, College of Engineering, Inha University, Incheon 402-751, Republic of Korea
| | - Subash C B Gopinath
- Faculty of Chemical Engineering Technology and Institute of Nano Electronic Engineering, Universiti Malaysia Perlis, Arau 02600, Perlis, Malaysia
| | - Baskaralingam Vaseeharan
- Nanobiosciences and Nanopharmacology Division, Biomaterials and Biotechnology in Animal Health Lab, Department of Animal Health and Management, Alagappa University, Science Campus 6th Floor, Karaikudi 630 004, Tamil Nadu, India
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19
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Mamedov T, Yuksel D, Ilgın M, Gürbüzaslan I, Gulec B, Mammadova G, Ozdarendeli A, Yetiskin H, Kaplan B, Islam Pavel ST, Uygut MA, Hasanova G. Production and Characterization of Nucleocapsid and RBD Cocktail Antigens of SARS-CoV-2 in Nicotiana benthamiana Plant as a Vaccine Candidate against COVID-19. Vaccines (Basel) 2021; 9:1337. [PMID: 34835268 PMCID: PMC8621474 DOI: 10.3390/vaccines9111337] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 11/06/2021] [Accepted: 11/10/2021] [Indexed: 12/25/2022] Open
Abstract
The COVID-19 pandemic has put global public health at high risk, rapidly spreading around the world. Although several COVID-19 vaccines are available for mass immunization, the world still urgently needs highly effective, reliable, cost-effective, and safe SARS-CoV-2 coronavirus vaccines, as well as antiviral and therapeutic drugs, to control the COVID-19 pandemic given the emerging variant strains of the virus. Recently, we successfully produced receptor-binding domain (RBD) variants in the Nicotiana benthamiana plant as promising vaccine candidates against COVID-19 and demonstrated that mice immunized with these antigens elicited a high titer of RBD-specific antibodies with potent neutralizing activity against SARS-CoV-2. In this study, we engineered the nucleocapsid (N) protein and co-expressed it with RBD of SARS-CoV-2 in Nicotiana benthamiana plant to produce an antigen cocktail. The purification yields were about 22 or 24 mg of pure protein/kg of plant biomass for N or N+RBD antigens, respectively. The purified plant produced N protein was recognized by N protein-specific monoclonal and polyclonal antibodies demonstrating specific reactivity of mAb to plant-produced N protein. In this study, for the first time, we report the co-expression of RBD with N protein to produce a cocktail antigen of SARS-CoV-2, which elicited high-titer antibodies with potent neutralizing activity against SARS-CoV-2. Thus, obtained data support that a plant-produced antigen cocktail, developed in this study, is a promising vaccine candidate against COVID-19.
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Affiliation(s)
- Tarlan Mamedov
- Department of Agricultural Biotechnology, Akdeniz University, Antalya 07058, Turkey; (D.Y.); (M.I.); (I.G.); (B.G.); (G.M.); (G.H.)
| | - Damla Yuksel
- Department of Agricultural Biotechnology, Akdeniz University, Antalya 07058, Turkey; (D.Y.); (M.I.); (I.G.); (B.G.); (G.M.); (G.H.)
| | - Merve Ilgın
- Department of Agricultural Biotechnology, Akdeniz University, Antalya 07058, Turkey; (D.Y.); (M.I.); (I.G.); (B.G.); (G.M.); (G.H.)
| | - Irem Gürbüzaslan
- Department of Agricultural Biotechnology, Akdeniz University, Antalya 07058, Turkey; (D.Y.); (M.I.); (I.G.); (B.G.); (G.M.); (G.H.)
| | - Burcu Gulec
- Department of Agricultural Biotechnology, Akdeniz University, Antalya 07058, Turkey; (D.Y.); (M.I.); (I.G.); (B.G.); (G.M.); (G.H.)
| | - Gulshan Mammadova
- Department of Agricultural Biotechnology, Akdeniz University, Antalya 07058, Turkey; (D.Y.); (M.I.); (I.G.); (B.G.); (G.M.); (G.H.)
| | - Aykut Ozdarendeli
- Department of Microbiology, Medical Faculty, Erciyes University, Kayseri 38280, Turkey; (A.O.); (H.Y.); (B.K.); (S.T.I.P.); (M.A.U.)
- Vaccine Research, Development and Application Center, Erciyes University, Kayseri 38280, Turkey
| | - Hazel Yetiskin
- Department of Microbiology, Medical Faculty, Erciyes University, Kayseri 38280, Turkey; (A.O.); (H.Y.); (B.K.); (S.T.I.P.); (M.A.U.)
- Vaccine Research, Development and Application Center, Erciyes University, Kayseri 38280, Turkey
| | - Busra Kaplan
- Department of Microbiology, Medical Faculty, Erciyes University, Kayseri 38280, Turkey; (A.O.); (H.Y.); (B.K.); (S.T.I.P.); (M.A.U.)
- Vaccine Research, Development and Application Center, Erciyes University, Kayseri 38280, Turkey
| | - Shaikh Terkis Islam Pavel
- Department of Microbiology, Medical Faculty, Erciyes University, Kayseri 38280, Turkey; (A.O.); (H.Y.); (B.K.); (S.T.I.P.); (M.A.U.)
- Vaccine Research, Development and Application Center, Erciyes University, Kayseri 38280, Turkey
| | - Muhammet Ali Uygut
- Department of Microbiology, Medical Faculty, Erciyes University, Kayseri 38280, Turkey; (A.O.); (H.Y.); (B.K.); (S.T.I.P.); (M.A.U.)
| | - Gulnara Hasanova
- Department of Agricultural Biotechnology, Akdeniz University, Antalya 07058, Turkey; (D.Y.); (M.I.); (I.G.); (B.G.); (G.M.); (G.H.)
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20
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Development of an Inactivated Vaccine against SARS CoV-2. Vaccines (Basel) 2021; 9:vaccines9111266. [PMID: 34835197 PMCID: PMC8624180 DOI: 10.3390/vaccines9111266] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 10/26/2021] [Accepted: 10/30/2021] [Indexed: 12/15/2022] Open
Abstract
The rapid spread of SARS-CoV-2 with its mutating strains has posed a global threat to safety during this COVID-19 pandemic. Thus far, there are 123 candidate vaccines in human clinical trials and more than 190 candidates in preclinical development worldwide as per the WHO on 1 October 2021. The various types of vaccines that are currently approved for emergency use include viral vectors (e.g., adenovirus, University of Oxford/AstraZeneca, Gamaleya Sputnik V, and Johnson & Johnson), mRNA (Moderna and Pfizer-BioNTech), and whole inactivated (Sinovac Biotech and Sinopharm) vaccines. Amidst the emerging cases and shortages of vaccines for global distribution, it is vital to develop a vaccine candidate that recapitulates the severe and fatal progression of COVID-19 and further helps to cope with the current outbreak. Hence, we present the preclinical immunogenicity, protective efficacy, and safety evaluation of a whole-virion inactivated SARS-CoV-2 vaccine candidate (ERUCoV-VAC) formulated in aluminium hydroxide, in three animal models, BALB/c mice, transgenic mice (K18-hACE2), and ferrets. The hCoV-19/Turkey/ERAGEM-001/2020 strain was used for the safety evaluation of ERUCoV-VAC. It was found that ERUCoV-VAC was highly immunogenic and elicited a strong immune response in BALB/c mice. The protective efficacy of the vaccine in K18-hACE2 showed that ERUCoV-VAC induced complete protection of the mice from a lethal SARS-CoV-2 challenge. Similar viral clearance rates with the safety evaluation of the vaccine in upper respiratory tracts were also positively appreciable in the ferret models. ERUCoV-VAC has been authorized by the Turkish Medicines and Medical Devices Agency and has now entered phase 3 clinical development (NCT04942405). The name of ERUCoV-VAC has been changed to TURKOVAC in the phase 3 clinical trial.
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21
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Mamedov T, Gurbuzaslan I, Yuksel D, Ilgin M, Mammadova G, Ozkul A, Hasanova G. Soluble Human Angiotensin- Converting Enzyme 2 as a Potential Therapeutic Tool for COVID-19 is Produced at High Levels In Nicotiana benthamiana Plant With Potent Anti-SARS-CoV-2 Activity. FRONTIERS IN PLANT SCIENCE 2021; 12:742875. [PMID: 34938305 PMCID: PMC8685454 DOI: 10.3389/fpls.2021.742875] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 11/08/2021] [Indexed: 05/05/2023]
Abstract
The coronavirus disease 2019 (COVID-19) pandemic, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread to more than 222 countries and has put global public health at high risk. The world urgently needs a safe, cost-effective SARS-CoV-2 vaccine as well as therapeutic and antiviral drugs to combat COVID-19. Angiotensin-converting enzyme 2 (ACE2), as a key receptor for SARS-CoV-2 infections, has been proposed as a potential therapeutic tool in patients with COVID-19. In this study, we report a high-level production (about ∼0.75 g/kg leaf biomass) of human soluble (truncated) ACE2 in the Nicotiana benthamiana plant. After the Ni-NTA single-step, the purification yields of recombinant plant produced ACE2 protein in glycosylated and deglycosylated forms calculated as ∼0.4 and 0.5 g/kg leaf biomass, respectively. The plant produced recombinant human soluble ACE2s successfully bind to the SARS-CoV-2 spike protein. Importantly, both deglycosylated and glycosylated forms of ACE2 are stable at increased temperatures for extended periods of time and demonstrated strong anti-SARS-CoV-2 activities in vitro. The half maximal inhibitory concentration (IC50) values of glycosylated ACE2 (gACE2) and deglycosylated ACE2 (dACE2) were ∼1.0 and 8.48 μg/ml, respectively, for the pre-entry infection, when incubated with 100TCID50 of SARS-CoV-2. Therefore, plant produced soluble ACE2s are promising cost-effective and safe candidates as a potential therapeutic tool in the treatment of patients with COVID-19.
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Affiliation(s)
- Tarlan Mamedov
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Turkey
- Institute of Molecular Biology and Biotechnology, Azerbaijan National Academy of Sciences, Baku, Azerbaijan
- *Correspondence: Tarlan Mamedov,
| | - Irem Gurbuzaslan
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Turkey
| | - Damla Yuksel
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Turkey
| | - Merve Ilgin
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Turkey
| | - Gunay Mammadova
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Turkey
| | - Aykut Ozkul
- Department of Virology, Faculty of Veterinary Medicine, Ankara University, Ankara, Turkey
- Biotechnology Institute, Ankara University, Ankara, Turkey
| | - Gulnara Hasanova
- Department of Agricultural Biotechnology, Akdeniz University, Antalya, Turkey
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22
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Margolin E, Verbeek M, de Moor W, Chapman R, Meyers A, Schäfer G, Williamson AL, Rybicki E. Investigating Constraints Along the Plant Secretory Pathway to Improve Production of a SARS-CoV-2 Spike Vaccine Candidate. FRONTIERS IN PLANT SCIENCE 2021; 12:798822. [PMID: 35058959 PMCID: PMC8764404 DOI: 10.3389/fpls.2021.798822] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 11/29/2021] [Indexed: 05/10/2023]
Abstract
Given the complex maturation requirements of viral glycoproteins and the challenge they often pose for expression in plants, the identification of host constraints precluding their efficient production is a priority for the molecular farming of vaccines. Building on previous work to improve viral glycoprotein production in plants, we investigated the production of a soluble SARS-CoV-2 spike comprising the ectopic portion of the glycoprotein. This was successfully transiently expressed in N. benthamiana by co-expressing the human lectin-binding chaperone calreticulin, which substantially increased the accumulation of the glycoprotein. The spike was mostly unprocessed unless the protease furin was co-expressed which resulted in highly efficient processing of the glycoprotein. Co-expression of several broad-spectrum protease inhibitors did not improve accumulation of the protein any further. The protein was successfully purified by affinity chromatography and gel filtration, although the purified product was heterogenous and the yields were low. Immunogenicity of the antigen was tested in BALB/c mice, and cellular and antibody responses were elicited after low dose inoculation with the adjuvanted protein. This work constitutes an important proof-of-concept for host plant engineering in the context of rapid vaccine development for SARS-CoV-2 and other emerging viruses.
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Affiliation(s)
- Emmanuel Margolin
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Wellcome Trust Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa
- Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- *Correspondence: Emmanuel Margolin,
| | - Matthew Verbeek
- Biopharming Research Unit, Department of Molecular and Cell Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Warren de Moor
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Ros Chapman
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Ann Meyers
- Biopharming Research Unit, Department of Molecular and Cell Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Georgia Schäfer
- Wellcome Trust Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- International Centre for Genetic Engineering and Biotechnology, Observatory, Cape Town, South Africa
| | - Anna-Lise Williamson
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Wellcome Trust Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Edward Rybicki
- Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- Biopharming Research Unit, Department of Molecular and Cell Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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